Bore Pipe Under a Sidewalk With a Recip Saw and Two Hose Clamps
The Problem
Getting an irrigation line across a sidewalk or paved path is the worst part of the run. You can't cut the concrete, hand-driving a pipe with a sledge deforms the end and stalls in compacted soil, and the water-jet method turns the hole into a mud slurry.
The Technique
The saw does the driving.
- Dig out on both sides of the walkway so you have room to work and a target to break through to.
- Lay a length of pipe alongside a reciprocating saw blade and strap the two together with a pair of hose clamps.
- Keep the blade fully retracted — not extended out — when you set it up. Measure the overlap so that when the saw runs, the tip of the pipe reciprocates without the pipe striking the saw's guard.
- Line the pipe up level at the hole, pull the trigger, and let the saw's stroke hammer the pipe forward through the soil under the slab. Steady pressure, and the pipe walks itself across.
Pro tip: The setup detail that makes or breaks this is step 3 — clamp position. The blade's stroke has to spend itself driving the pipe, not slamming the pipe's back end into the saw. Check the clearance by hand-cycling the blade before you commit.
Safety note: Never drive pipe blind under pavement without knowing what's down there — gas, electric, and water services run shallow along walkways. Call 811 (or your local utility-locate service) before you dig or bore, wear eye protection, and keep your hands clear of the reciprocating pipe.